I was out for a whole year. Couldnt run a step. Tried everything (cortisone...stim, ice, etc..) it wasnt until I got into the gym that it cleared up...within a month i was back and havent had a problem since...
Some of my staple workouts..
1) use a big rubber band around your ankles and walk while stretching it. walk forwards and sideways...
2) plant one foot on the ground and the other in the air behind you. If your left foot is on the ground have your right hand be at a right angle next to your head. bend from the waist to the opposite side and touch the ground next to your left foot..repeat many times for both sides..
when you get better at this you can move up to a balance board to work your stabalizers harder.
3) I would also do alot of ab, back and hanstring work...
mostly with a medecine ball...
Mind you i did this 5 days a week with no running...
you have to become obsessed with getting healthy...